The present invention relates to a reflecting mirror for a vehicle lamp that can improve reflecting efficiency and reduce an area ineffective in forming light distribution by eliminating an area, which is shaded from rays of light emitted from a light source, on a reflective surface of the reflecting mirror, as well as to a method of manufacturing such a reflecting mirror.
One basic construction of a vehicle lamp is as follows. The vehicle lamp includes a lamp body having an opening at one end thereof; a reflecting mirror arranged within the lamp body or a reflecting portion formed by applying a reflection treatment to a part of the lamp body; and an outer lens that covers the opening of the lamp body. The reflective surface of the reflecting mirror or the reflecting portion is formed by a paraboloid of revolution or the like, which is symmetrical around the optical axis of the lamp.
FIG. 12 shows a positional relationship between a reflecting mirror "a" having the shape of a paraboloid of revolution and a lamp bulb "b". The lamp bulb "b" is attached to the reflecting mirror "a" with the central axis K--K of the lamp bulb "b" extending along the optical axis of the reflecting mirror "a".
A glass bulb "c" of the lamp bulb "b" has an end portion on the reflecting mirror side accommodated in a socket "d", and power is supplied to a filament "e" inside the glass bulb "c" from a power supply (not shown).
In the thus constructed reflecting mirror "a", rays of light from the lamp bulb "b" is shaded with a socket "d" that supports the bulb "c". As a result, the reflective surface of the reflecting mirror "a" has an area onto which the rays of light are not incident.
Specifically, in FIG. 12, out of rays of light "f", "f", . . . emitted from light emitting reference point F of the filament e, part of such rays of light advancing toward the reflective surface of the reflecting mirror "a" are shaded by the socket "d". As a result, the rays of light are not incident onto the area within such a range as indicated by DA in FIG. 12, thus leaving the area ineffective in manufacturing luminous intensity distribution.